piano vocalism scores

you may go to esplanade national library, there gotta be a wide range of scores and more...

may also check out this music store list

http://www.yellowpages.com.sg/newiyp/yp/search2008.do?N=4290587475&searchCriteria=Music-Scores&applicationInd=yp&accessType=0&searchType=1&searchTab=CT&navFromHomePage=NavFromHomePage&dimValName=Music-Scores&urlIdentifier=cat&navOrder=Music-Scores

hope it helps

We know many good places where can buy many profassional music books in China but few people kown it in Singapore。But in my opinion you may try to find some music school or music collage 。Because generally many book shop which sell profassional music will seat